A. The initial mass of the sample is 6.35
B. The time taken for 0.3 mg of the sample to remain is 66 days
A. Determination of the initial mass of the sample
We'll begin by calculating the number of half-lives that has elapsedHalf-life (t½) = 15 days
Time (t) = 10 days
Number of half-lives (n) =?n = t / t½
n = 10 / 15
n = ⅔Finally, we shall determine the initial mass of the sample.Number of half-lives (n) = ⅔
Amount remaining (N) = 4 mg
Initial amount (N₀) =?[tex]N_0 = N \times {2}^{n} \\ N_0 = 4 \times {2}^{2 \div 3} \\ N_0 = 6.35 \: mg[/tex]
Therefore, the initial mass of the sample is 6.35 mg
B. Determination of the time
We'll begin by calculating the number of half-lives that has elapsedAmount remaining (N) = 0.3 mg
Initial amount (N₀) = 6.35 mg
Number of half-lives (n) =?[tex]{2}^{n} = \frac{N_0}{N} \\ \\ {2}^{n} = \frac{6.35}{0.3} \\ \\ {2}^{n} = 21.167 \\ take \: the \: log \: of \: both \: side \\ log \: {2}^{n} = log \: 21.167 \\ nlog2 = log \: 21.167 \\ divide \: both \: side \: by \: log2 \\ \\ n = \frac{log \: 21.167}{log2} \\ \\ n = 4.4[/tex]
Finally, we shall determine the timeNumber of half-lives (n) = 4.4
Half-life (t½) = 15 days
Time(t) =?t = n × t½
t = 4.4 × 15
t = 66 daysTherefore, it will take 66 days for 0.3 mg of the sample to remain.
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A system which allows both mass and energy to flow into the surroundings is called
Answer:
An open system can exchange both energy and matter with its surroundings. The stovetop example would be an open system, because heat and water vapor can be lost to the air.
Explanation:
How many milliliters of a stock solution of 12.1 M HNO3 would be needed to prepare 0.500 L of 0.500 M HNO3
Answer:
(5.00M)(X) = (0.120L)(0.470M)
X = (0.120)(0.470)/(5.00)
0.01128
Explanation:
12.1 M HNO3 would be needed to prepare 0.500 L of 0.500 M HNO3 stock solution is 0.01128 milliliters.
What is stock solution ?
The ideal way to define stock solutions is as concentrated solutions with precise, known concentrations that will be diluted for later laboratory usage. Even though you may decide against making stock solutions, doing so may help you run your business more efficiently and save you a ton of time and money.
where C1 x V1 = C2 x V2. Stock concentration, C1 ( beginning concentration ) V1 is the amount of stock needed to make the new solution. C2 is the concentration of a fresh or effective solution.
( 5.00M ) ( X ) = ( 0.120 liter ) ( 0.470 M )
Then, X = 0.120 × 0.470 ÷ 5.00
= 0.01128 milliliters.
Thus, 12.1 M HNO3 would be needed to prepare 0.500 L of 0.500 M HNO3 stock solution is 0.01128 milliliters.
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What is the acceleration of a 10 kg pushed by a 5N force
Answer:
0.5 m/s²Explanation:
The acceleration of an object given it's mass and the force acting on it can be found by using the formula
[tex]a = \frac{f}{m} \\ [/tex]
f is the force
m is the mass
From the question we have
[tex]a = \frac{5}{10} = \frac{1}{2} = 0.5 \\ [/tex]
We have the final answer as
0.5 m/s²Hope this helps you
whats the formula for lithium nitride
Answer:
Lithium nitride. Trilithium nitride. 26134-62-3. Lithium nitride (Li3N) Li3N.
what happened if you poured lava on snow
Answer:
This is what could happen:
Explanation:
When lava meets ice, the resulting mess can cause flooding, destroy valuable resources and even produce explosions.
Answer: When lava meets ice, it neither explodes nor tunnels through; rather, it forms strange-looking bubbles.
Explanation:
Which class of macromolecule was described as being most like the hydrocarbons?.
Answer:
Fats........................
Lipids is the class of macromolecule was described as being most like the hydrocarbons.
what are Macromolecules ?Macromolecules are bigger molecules of large size and made of smaller molecules called as monomers, Polymers are macromolecules.
All Macromolecules are not like the hydrocarbon because the macromolecules not only consists of C and H atoms but also N and O.
Macromolecules are classified into 4 types
Proteins , Carbohydrates , Lipids and Nucleic Acids
Lipids is the class of macromolecule was described as being most like the hydrocarbons.
Lipids are a broad category of chemicals that are mostly nonpolar in nature.
This is due to the fact that they are hydrocarbons with nonpolar carbon–carbon or carbon–hydrogen bonds.
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Which of the following is considered quantitative data?
A. Appearance
B. Smell
C. Temperature
Answer:
Temperature
Explanation:
This is because quantitative data include numerical values for example 10 degrees Celsius. However the others are qualitative data because the research can be described but not with numbers like your appearance is very nice.
Hope this helps :P
Answer:
Quantitative data is the type of data whose value is measured in the form of numbers or counts, with a unique numerical value associated with each data set. Also known as numerical data, quantitative data further describes numeric variables (e.g. How many? How often? How much?)
Explanation:
so its temp
PLEASEE HELPPP!!!!
Hydrogen bonds can be found between molecules of which substance?
1.) CH4
2.) H2
3.) C4H10
4.) NH3
Answer:
3.) NH3
Brainliest if this helps please? (:
Please help me no links
if good answer you get brainliest
Answer:
plutonic rocks are formed when magma cools and solidifies underground This shows us if the rock is plutonic or volcanic. When magma cools underground, it cools super slow and when lava cools above ground, it cools faster. When magma and lava cool, mineral crystals start to form in the molten rock.
Explanation:
i hope this is correct
Earth’s spheres interact in a system that makes up all of the matter, energy, and processes within Earth’s boundary. You learned about the different spheres in this lesson and how spheres are not isolated, but they interact. In the space below, explain how the biosphere relies on the other spheres for survival.
Answer:
Explanatthe tryposphereion:
Question ( please help me )
1 . Which diagram shows pure substance that are elements
2. Which diagram shows pure substance are compounds
3. Which diagram shows a mixture of compounds
4. Which diagram shows a mixture of elements
5. Which diagram shows a mixture of an element and a compound
Answer:
1. F, H, E
2. A, D, I
3. G
4. E, B, H
5. C
Explanation:
How many dozens of silver atoms are in the piece of jewelry?.
Based on properties of elements in the periodic table, which element is the best conductor of thermal energy?.
Answer:
Silver
Explanation:
Silver has the highest thermal conductivity of any element and the highest light reflectance.
if we change the pH of a substance is this a physical change chemical change or both?
Answer:
chemical change
ExplanationC:
What is the formula for the ionic compound formed by calcium and selenium?
Answer:
CaSe
Explanation:
not sure!!
Se dispone de un recipiente de 60 litros que contiene un gas de 1,64 atm y a una temperatura de 100K ¿Cuántos moles de gas hay? *
En este caso, dado que se describe un gas del que se conoce el volumen (60L), la presión (1.64 atm) y la temperatura (100K), es posible usar la ecuación del gas ideal para calcular los moles que hay presentes a estas condiciones:
[tex]PV=nRT[/tex]
Ahora, despejamos las moles del gas como sigue:
[tex]n=\frac{PV}{RT}[/tex]
Finalmente, reemplazamos los valores dados, teniendo en cuenta que R es 0.08206 en atmosferas, litros y Kelvin:
[tex]n=\frac{1.64atm*60L}{0.08206*100K}\\\\n=11.8mol[/tex]
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https://brainly.com/question/15890754 https://brainly.com/question/229468114,756 rounded to nearest thousand
Answer:
5,000
Explanation:
When rounding to the thousands place, you look at the digit in the hundreds place, if the digit is less than 5 you round down. For example if the number was "4,456," we would round to "4,000." But, since the digit in the hundreds place is 7, which is greater than 4, you round up to "5,000."
calculate the number of atoms in 1009g of neon
This is kind of a pretty easy question:
- In order to get the number of atoms/entities of Neon, you will have to turn that 1009g of Neon into moles
-And then you have to use the moles and calculate it using Avogadro's Number which is 6.02 x 10^23
number of moles = mass/molar mass of element/compound
n = 1009g/20.18g/mol
n = 50 mol
Number of atoms/entities = 50 x (6.02 x 10^23)
Number of atoms in 1009g of neon is 3.01 x 10^25 (scientific notation because its a really long number)
is isopropyl alcohol the same as hydrogen peroxide
Answer:
Unlike isopropanol, hydrogen peroxide is not a type of alcohol. You might recognize its chemical formula, H2O2, as being similar to that of water (H2O). The difference is that hydrogen peroxide has two oxygen atoms instead of one. That one extra oxygen atom makes it a strong oxidizer.
In which process do particles move closer together but remain in motion?
А condensation
B
diffusion
с
evaporation
D
freezing
Answer: c
Explanation: the particles stay together but has some gain more heat they break apart.
22) Calculate the energy of a photon of radiation with a frequency of 9.50 x 1013 Hz.
The energy of the photon with a frequency of 9.50×10¹³ Hz is 6.29×10¯²⁰ J
From the question given above, the following data were obtained:
Frequency (f) = 9.50×10¹³ Hz
Planck's constant (h) = 6.626×10¯³⁴ Js
Energy (E) =?The energy of the photon can be obtained as follow:
E = hf
E = 6.626×10¯³⁴ × 9.50×10¹³
E = 6.29×10¯²⁰ JTherefore, the energy of the photon is 6.29×10¯²⁰ J
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in hydrogen iodide __________________ are the most important intermolecular forces.
Answer:
dipole-dipole forces
Explanation:
The important intermolecular force in hydrogen iodide HI is dipole- dipole forces. This force is arising due to the partial charge separation and permanent dipole moment.
What is dipole-dipole force?There are various intermolecular forces which binds two atoms chemically to form a compound. Ionic bonding, covalent bonding, dipole -dipole force, hydrogen bonding, Van der Waals force etc are some of them.
Dipoles are opposite charges separated by a small distance. Dipole -dipole force is generated between the atoms when they have partial charge separation and this creates a permanent dipole moment.
Hydrogen is an electropositive atom and iodine is slightly electronegative. This difference in electronegativities leads to the bonded electrons more attracted towards iodine result in partial charge separation and dipole-dipole force.
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Consider the Sy2 reaction between 1-bromo-2-methylpropane and methoxide. Add curved arrows to the starting materials to
indicate the flow of electrons. Draw the product species to show the balanced equation, including nonbonding electrons and
formal charges.
H2
Н.С.
Br:
-CH3
product
n Shot
07.42 PI
H
+
CH3
n Shot
.07.13 P1
Draw curved arrows.
Draw the products. The bromide ion has been drawn
for you.
Draw
Select
Rings
More
Erase
Question"
Select
Draw
Rings
More
Erase
h Shot
10.36 PI
///
С
Br
O
С
Br
o
n Shot
-2
Answer:
sdfs
Explanation:
dfssdf
When 1-bromo-2-methylpropane is reacted with methoxide the same product 1-methylprop-2-ene is obtained. This reaction is attached in image below:
What is SN₂ reaction ?The SN2 reaction is a nucleophilic substitution reaction that breaks one bond while forming another. The rate-determining step of the reaction involves two reacting species. SN2 is an abbreviation for Substitution Nucleophilic Bimolecular.
The reaction is bimolecular because two molecules are present in the transition state, as indicated by the number 2 in the SN2 symbol. As a result, the rate of the reaction is affected by the concentrations of both the nucleophile and the substrate.
The SN2 reaction is a nucleophilic substitution with two components in the rate determining step. -SN2 reactions are bimolecular, with bond-forming and bond-breaking steps occurring simultaneously. There is no intermediate in -SN2 reactions.
Thus, product 1-methylprop-2-ene is obtained.
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How many molecules are in 25.3g of C2H4O
Answer:
0.57 molecules
Explanation:
HELP PLEASE ASAP!!!!!
The best lewis structure, adhering to formal charge rules, of IO4-, has how many bonding pairs of electrons around the iodine atom?
Answer:
try using this calculator
wolfram alpha lewis structure calculator
Explanation:
The best Lewis structure, adhering to formal charge rules, of IO₄⁻, has eight bonding pairs of electrons around the iodine atom.
A Lewis Structure is a very simplified representation of the valence shell electrons in a molecule. It is used to show how the electrons are arranged around individual atoms in a molecule.
The shared pairs of electrons are drawn as lines between atoms, while lone pairs of electrons are drawn as dots next to atoms.
They also display the total number of lone pairs present in each of the atoms that constitute the molecule.
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A sample of a gas in a 4L container at 300K has a pressure of 1 atm. If the
temperature is increased to 600K and the volume is decreased to 2L , the
pressure is likely to be closest to which of the following? *
O 0.5 atm
1 atm
4 atm
2 atm
The final pressure of the gas in the container is 4 atm
From the question given above, the following data were obtained:
Initial volume (V₁) = 4 L
Initial temperature (T₁) = 300 K
Initial pressure (P₁) = 1 atm
Final temperature (T₂) = 600 K
Final volume (V₂) = 2 L
Final pressure (P₂) =?Using the combine gas equation, we can obtain the final pressure of the gas as illustrated below:[tex]\frac{P_{1} V_{1} }{T_{1}} = \frac{P_{2} V_{2}}{T_{2}}\\\\\frac{1 * 4}{300} = \frac{P_{2} * 2}{600} \\\\[/tex]
Cross multiply
300 × 2 × P₂ = 4 × 600
600 × P₂ = 2400
Divide both side by 600
[tex]P_{2} = \frac{2400}{600} \\\\[/tex]
P₂ = 4 atmTherefore, the final pressure of gas is 4 atm.
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bonding and kinetic energy quick check
1. The internal energy within a system associated with the motion of particles and that can be added to a substance is called (1 point)
o temperature
O kinetic energy
O thermal energy
O electrostatic forces
2. which statement describes the effect of adding more energy to a system, assuming a phase change does not occur?
0 the particles within the system will have greater motion and the temperature will increase
0 the particles within the system will have greater motion and the temperature will be grace
0 particles within the system will have less motion and the temperature will increase
0 the particles within the system will have less motion and the temperature will decrease
3. which statement correctly describes how a tractions that holds particles break
0 attractions occur due to gravitational forces when particles move fast enough these forces can no longer keep particles together
0 attractions due to Electrostatic forces when particles move fast enough these forces can no longer keep particles together
0 attractions due to electrostatic forces when particles have low enough energy these forces can no longer keep particles together
0 attractions occurred due to gravitational forces when particles have low enough energy these forces can no longer keep particles together
4. Which statement explains why a rubber band analogy is not a perfect comprehension for Bonds in a substance when considering phases change
0 for a phase change from solid to liquid the bonds do not break completely and particles can still slide past each other
0 for a phase change from liquid to gas the bonds do not break completely the particles can still slide past each other
0 for a phase change from liquid to gas the bonds break completely and of particles can independently of each other
0 phase change from solid to liquid the bond breaks completely particles can move independently of each other
5.the boiling point of benzene is 80°C. which pair of samples will have the same average kinetic energy of benzene molecules?
0 two samples of gaseous benzene, at 80°C and the other 90°C
0 two samples of liquid benzene, one at 70°C and the other at 80°
0 a sample of liquid benzene at 70°C and a sample of gaseous benzene at 90°C
0 a sample of liquid benzene at 80°C and a sample of gaseous benzene at 80°celectric
When energy is added to a system during phase change, the particles move faster.
When a substance is heated, the internal energy within a system associated with the motion of particles and that can be added to a substance is called thermal energy.
During a phase change, when more energy is added to the system, the particles within the system will have greater motion and the temperature will increase.
The attractions that hold molecules together are electrostatic forces. The correct statement about the attractions that hold particles is that attractions between particles break when attractions due to Electrostatic forces when particles move fast enough these forces can no longer keep particles together.
Rubber band is not a perfect comprehension for Bonds in a substance when considering phases change because for a phase change from liquid to gas the bonds do not break completely the particles can still slide past each other.
The pair of samples that will have the same average kinetic energy of benzene molecules is a sample of liquid benzene at 80°C and a sample of gaseous benzene at 80°C.
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Which sample is a pure substance?zinc oxidesugar dissolved in waterpond watersoil.
Answer:
Oxide sugar dissolved in water pond
because water + sugar= sugar melts but the oxide purifys the water.
Explanation:
#carryonlearning!
Can elements from group 1 and 2 show up as pure elements in nature? Except Hydrogen
Answer:
No. Although alkali metals and alkaline earth metals are found in nature, they are not found as pure elements. Group 1 and 2 are found in their chemical compounds, not pure form.
Define the mass number of an atom
Answer:
The mass number of an atom, which is also called the atomic mass number, is the total number of protons and neutrons in an atom,
Explanation:
Hope this is helpful.
